/*
 * Copyright 2009 Cedric Priscal
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.walkera.serialndkdemo;

import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.util.Log;

/**
 * Created by lihaiping on 2016/8/31.
 */

public class SerialPortNdk {
    private static final String TAG = "SerialPortNdk";

    /*
     * Do not remove or rename the field mFd: it is used by native method close();
     */
    private FileDescriptor mFd=null;
    private FileInputStream mFileInputStream=null;
    private FileOutputStream mFileOutputStream=null;

    public SerialPortNdk(File device, int baudrate, int flags) throws SecurityException, IOException {

		/* Check access permission */
		if (!device.canRead() || !device.canWrite()) {
			try {
				/* Missing read/write permission, trying to chmod the file */
				Process su;
                /*添加判断'/system/bin/su'和'/system/xbin/su'是否存在*/
                if (new File("/system/bin/su").exists()) {
                    Log.d(TAG, "SerialPortNdk: /system/bin/su exist");
                    su = Runtime.getRuntime().exec("/system/bin/su");
                }
                else {
                    if (new File("/system/xbin/su").exists()){//存在
                        Log.d(TAG, "SerialPortNdk: /system/xbin/su exist");
                        su = Runtime.getRuntime().exec("/system/xbin/su");
                    }else{
                        Log.e(TAG, "SerialPortNdk: /system/bin/su and /system/xbin/su inexistence");
                        /*如果都不存在，就抛出一个异常*/
                        throw new SecurityException();
                    }
                }

				String cmd = "chmod 666 " + device.getAbsolutePath() + "\n" + "exit\n";
				su.getOutputStream().write(cmd.getBytes());
				if ((su.waitFor() != 0) || !device.canRead() || !device.canWrite()) {
                    /*抛出一个安全异常*/
					throw new SecurityException();
				}
			} catch (Exception e) {
				e.printStackTrace();
				throw new SecurityException();
			}
		}

		mFd = open(device.getAbsolutePath(), baudrate, flags);
		if (mFd == null) {
			Log.e(TAG, "native open returns null");
			throw new IOException();
		}
		mFileInputStream = new FileInputStream(mFd);
		mFileOutputStream = new FileOutputStream(mFd);
    }

    // Getters and setters
    public InputStream getInputStream() {
        return mFileInputStream;
    }

    public OutputStream getOutputStream() {
        return mFileOutputStream;
    }


    // JNI
    private native static FileDescriptor open(String path, int baudrate, int flags);
    public  native void close();
    public  native String getNdkStr();

    static {
        System.loadLibrary("serialport");
    }
}
